diff --git a/cmake/LLVM.cmake b/cmake/LLVM.cmake
index 11472060a6..0e570f5a21 100644
--- a/cmake/LLVM.cmake
+++ b/cmake/LLVM.cmake
@@ -335,7 +335,6 @@
     "${PROG_NAME}${CMAKE_EXECUTABLE_SUFFIX}"
     HINTS "${LLVM_BINDIR}" "${LLVM_CONFIG_LOCATION}"
     DOC "${DOCSTRING}"
-    NO_DEFAULT_PATH
     NO_CMAKE_PATH
     NO_CMAKE_ENVIRONMENT_PATH
   )
@@ -346,7 +345,12 @@
   endif()
 endmacro()
 
-find_program_or_die(CLANG "clang" "clang binary")
+if(DEFINED CMAKE_C_COMPILER) # TODO: this assumes we are using clang
+  set(CLANG "${CMAKE_C_COMPILER}")
+  message(STATUS "Using clang: ${CLANG}")
+else()
+  find_program_or_die(CLANG "clang" "clang binary")
+endif()
 execute_process(COMMAND "${CLANG}" "--version" OUTPUT_VARIABLE LLVM_CLANG_VERSION RESULT_VARIABLE CLANG_RES)
 find_program_or_die(CLANGXX "clang++" "clang++ binary")
 execute_process(COMMAND "${CLANGXX}" "--version" OUTPUT_VARIABLE LLVM_CLANGXX_VERSION RESULT_VARIABLE CLANGXX_RES)
@@ -925,9 +929,15 @@
 
 #####################################################################
 
-execute_process(COMMAND "${CLANG}" "--print-resource-dir" OUTPUT_VARIABLE RESOURCE_DIR)
-string(STRIP "${RESOURCE_DIR}" RESOURCE_DIR)
-set(CLANG_RESOURCE_DIR "${RESOURCE_DIR}" CACHE INTERNAL "Clang resource dir")
+if (NOT DEFINED CLANG_RESOURCE_DIR)
+  execute_process(COMMAND "${CLANG}" "--print-resource-dir" OUTPUT_VARIABLE RESOURCE_DIR)
+  string(STRIP "${RESOURCE_DIR}" RESOURCE_DIR)
+  set(CLANG_RESOURCE_DIR "${RESOURCE_DIR}" CACHE INTERNAL "Clang resource dir")
+endif()
+
+set(CLANG_OPENCL_HEADERS "${CLANG_RESOURCE_DIR}/include/opencl-c.h"
+		"${CLANG_RESOURCE_DIR}/include/opencl-c-base.h")
+message(STATUS "clang OpenCL Headers: ${CLANG_OPENCL_HEADERS}")
 
 ##########################################################